remove username blacklist validation from login action

src/Controller/UserController.php

@@ -618,18 +618,6 @@ class UserController extends AbstractController
             );
         }
 
-        // Validate username blacklist
-        if (in_array(mb_strtolower($username), array_map('mb_strtolower', (array) explode('|', $this->getParameter('app.add.user.name.blacklist')))))
-        {
-            return $this->redirectToRoute(
-                'user_login',
-                [
-                    'username' => $request->get('username'),
-                    'error'    => $translator->trans('Username reserved by node!')
-                ]
-            );
-        }
-
         // Validate username exist
         if (!$hash = $this->_hash($client, $namespace, $username))
         {